mongodb条件操作符

这节来说说mongodb条件操作符，"$lt", "$lte", "$gt", "$gte", "$ne"就是全部的比较操作符，对应于"<", "<=", ">", ">=","!="。

原子操作符："$and“, "$or“, "$nor“。

or查询有两种方式：一种是用$in来查询一个键的多个值，另一种是用$or来完成多个键值的任意给定值。$in相当于SQL语句的in操作。

$nin不属于。

$not与正则表达式联合使用时候极其有用，用来查询哪些与特定模式不匹配的文档。

$slice相当于数组函数的切片，检索一个数组文档并获取数组的一部分。限制集合中大量元素节省带宽。理论上可以通过 limit() 和 skip() 函数来实现，但是，对于数组就无能为力了。 $slice可以指定两个参数。第一个参数表示要返回的元素总数。第二个参数是可选的。如果使用的话，第一个参数定义的是偏移量，而第二个参数是限定的个数。第二个参数还可以指定一个负数。

$mod取摸操作。

$size操作符允许对结果进行筛选，匹配指定的元素数的数组。

$exists操作符允许返回一个特定的对象。注意：当前版本$exists是无法使用索引的，因此，使用它需要全表扫描。

$type操作符允许基于BSON类型来匹配结果。

1. 插入一些数据

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> use ttlsa_com switched to db ttlsa_com > db.mediaCollection.insert({ "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : ["Keanu Reeves","Carry-Anne Moss","Laurence Fishburne","Hugo Weaving","Gloria Foster","Joe Pantoliano"] }) > db.mediaCollection.insert({ "Type" : "DVD", Title : "Blade Runner", Released : 1982 }) > db.mediaCollection.insert({ "Type" : "DVD", Title : "Toy Story 3", Released : 2010 })

2. $gt (greater than)

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> db.mediaCollection.find({ Released : {$gt : 2000} }, { "Cast" : 0 }).toArray() [         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

3. $gte(greater than or equal to)

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> db.mediaCollection.find( { Released : {$gte : 1999 } }, { "Cast" : 0 } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

4. $lt (less than)

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> db.mediaCollection.find( { Released : {$lt : 1999 } }, { "Cast" : 0 } ).toArray() [         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         } ]

5. $lte (less than or equal to)

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> db.mediaCollection.find( {Released : {$lte: 1999}}, { "Cast" : 0 } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999         },         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         } ]

6. 组合使用

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> db.mediaCollection.find( {Released : {$gte: 1990, $lt : 2010}}, { "Cast" : 0 } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999         } ]

7. $ne (not equals)

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> db.mediaCollection.find( { Type : "DVD"} ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         },         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ] > db.mediaCollection.find( { Type : "DVD", Released : { $ne: 1999}} ).toArray() [         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

8. $in/$or

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> db.mediaCollection.find( {Released : {$in : [1999,2008,2009] } }, { "Cast" : 0 } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999         } ]

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> db.mediaCollection.find( {$or :  [ {Released:1999}, {Released:2008}, {Released:2009} ] } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         } ]

9. $nin

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> db.mediaCollection.find( {Type : "DVD" }, { "Cast" : 0 }).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999         },         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ] > db.mediaCollection.find( {Released : {$nin : [1999,2008,2009] },Type : "DVD" }, { "Cast" : 0 }).toArray() [         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

10.  $all

与$in有点相似，只不过$all是所有属性要与文档匹配。$in只匹配其一就行。

1 2	> db.mediaCollection.find( { Released : {$all : ["2010","2009"] } }, { "Cast" : 0 } ).toArray() [ ]

11.  多个表达式

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> db.mediaCollection.find({ $or : [ { "Title" : "Toy Story 3" }, { "ISBN" : "987-1-4302-3051-9" } ] } ).toArray() [         {                 "_id" : ObjectId("5353462f93efef02c962da71"),                 "Type" : "Book",                 "Title" : "Definitive Guide to MongoDB, the",                 "ISBN" : "987-1-4302-3051-9",                 "Publisher" : "Apress",                 "Author" : [                         "Membrey, Peter",                         "Plugge, Eelco",                         "Hawkins, Tim"                 ]         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

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> db.mediaCollection.find({ "Type" : "DVD", $or : [ { "Title" : "Toy Story 3" }, { "ISBN" : "987-1-4302-3051-9" } ] }).toArray() [         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

11. 切片

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> db.mediaCollection.find({"Title" : "Matrix, The"}).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: 3}}).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne"                 ]         } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: -3}}).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: [2,3] }}).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster"                 ]         } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: [-5,4] }}).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster"                 ]         } ]

12. $mod

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> db.mediaCollection.find( { Type : "DVD", Released : { $mod: [2,0] } } ).toArray() [         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ] > db.mediaCollection.find( { Type : "DVD", Released : { $mod: [2,1] } } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         } ]

13. $size

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> db.mediaCollection.find( { Tracklist : {$size : 2} } ).toArray() [         {                 "_id" : ObjectId("5353463193efef02c962da73"),                 "Type" : "CD",                 "Artist" : "Nirvana",                 "Title" : "Nevermind",                 "Tracklist" : [                         {                                 "Track" : "1",                                 "Title" : "Smells like teen spirit",                                 "Length" : "5:02"                         },                         {                                 "Track" : "2",                                 "Title" : "In Bloom",                                 "Length" : "4:15"                         }                 ]         } ] > db.mediaCollection.find( { Cast : {$size : 1} } ).toArray() [ ] > db.mediaCollection.find( { Cast : {$size : 6} } ).toArray() [         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         } ]

14. $exists

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> db.mediaCollection.find( { Author : {$exists : true } } ).toArray() [         {                 "_id" : ObjectId("5353462f93efef02c962da71"),                 "Type" : "Book",                 "Title" : "Definitive Guide to MongoDB, the",                 "ISBN" : "987-1-4302-3051-9",                 "Publisher" : "Apress",                 "Author" : [                         "Membrey, Peter",                         "Plugge, Eelco",                         "Hawkins, Tim"                 ]         } ] > db.mediaCollection.find( { Author : {$exists : false } } ).toArray() [         {                 "_id" : ObjectId("5353462f93efef02c962da72"),                 "Type" : "CD",                 "Artist" : "Nirvana",                 "Title" : "Nevermind"         },         {                 "_id" : ObjectId("5353463193efef02c962da73"),                 "Type" : "CD",                 "Artist" : "Nirvana",                 "Title" : "Nevermind",                 "Tracklist" : [                         {                                 "Track" : "1",                                 "Title" : "Smells like teen spirit",                                 "Length" : "5:02"                         },                         {                                 "Track" : "2",                                 "Title" : "In Bloom",                                 "Length" : "4:15"                         }                 ]         },         {                 "_id" : ObjectId("53548225d85b463e729a2e57"),                 "Type" : "DVD",                 "Title" : "Matrix, The",                 "Released" : 1999,                 "Cast" : [                         "Keanu Reeves",                         "Carry-Anne Moss",                         "Laurence Fishburne",                         "Hugo Weaving",                         "Gloria Foster",                         "Joe Pantoliano"                 ]         },         {                 "_id" : ObjectId("5354823fd85b463e729a2e58"),                 "Type" : "DVD",                 "Title" : "Blade Runner",                 "Released" : 1982         },         {                 "_id" : ObjectId("53548254d85b463e729a2e59"),                 "Type" : "DVD",                 "Title" : "Toy Story 3",                 "Released" : 2010         } ]

15. $type

根据BSON类型来检索集合中匹配的结果。

MongoDB中可以使用的类型如下表所示：

类型描述	类型值
Double	1
String	2
Object	3
Array	4
Binary data	5
Object id	7
Boolean	8
Date	9
Null	10
Regular expression	11
JavaScript code	13
Symbol	14
JavaScript code with scope	15
32-bit integer	16
Timestamp	17
64-bit integer	18
Min key	255
Max key	127

下面这个实例是查询嵌入对象。

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> db.mediaCollection.find ( { Tracklist: { $type : 3 } } ).toArray() [         {                 "_id" : ObjectId("5353463193efef02c962da73"),                 "Type" : "CD",                 "Artist" : "Nirvana",                 "Title" : "Nevermind",                 "Tracklist" : [                         {                                 "Track" : "1",                                 "Title" : "Smells like teen spirit",                                 "Length" : "5:02"                         },                         {                                 "Track" : "2",                                 "Title" : "In Bloom",                                 "Length" : "4:15"                         }                 ]         } ]